Organic semiconductor material and low power function electrode of an organic light-emitting diode (OLED) are degraded easily by oxygen and mist. In the process of commercialization of OLED, there are always challenges to increase the stability and the useful time of the elements of OLED by effective packaging technology. The conventional packaging method can not meet the requirement cause of the high cost and without flexibility. It becomes a trend to use atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) technology to produce a flexible barrier film.
The rate of ALD process depositing high compactness and low defect inorganic thin film such as aluminum oxide (Al2O3) is slow. It may take 200˜300 minutes to reach the required packaging thickness about 2030 nm of an OLED by the ALD process. Without decreasing the cost effectively, the adoption in the market is low. Although the deposition rate of PECVD process is faster, plasma induced damage may occur in the elements of an OLED easily. With the combination of the advantages of these two deposition processes, dozens of atomic layers are deposited about 20 minutes by the ALD process to form a non-defect thin film (i.e. aluminum oxide layer) with the thickness about 2 nm, and a thicker Silicon Nitride (SiNx) layer is deposited by the PECVD process to against the aluminum oxide layer from hydrolysis in the air. Because of the non-defect thin film produced by the ALD process is compact, the non-defect thin film may protect the elements of the OLED from the influence of plasma induced damage during the PECVD process. It may substantially decrease the process time from 4-5 hours to 0.5 hour forming the barrier film.
However, in recent technology, the deposition steps during the ALD and the PECVD process are performed in two different chambers individually. It does not only increase the costs, but also expose the elements of the unfinished packaging OLED in the environment during the transfer process and cause low quality of the barrier film. Besides, the ALD process is entirely different from the PECVD process. The PECVD process must uniform the mix process gas via a showerhead, and produce plasma to ionize the process gas as a coating precursor reactant. For the reason, the showerhead is designed having 1˜3 layers of gas diffusion space as buffer regions, so as to carry out the purpose of outputting gas uniformly. However, the ALD process emphasizes how to make the coating precursor reactant distribute and adhere on the substrate saturantly in the lowest cycle time. Hence, if the ALD process is performed via the showerhead of the PECVD process, for the purpose of saturate distribution, the process gas have to be filled in the showerhead and the entire chamber. Thus, the cycle time and the gas volume of use will increase.